Contents

Visiting many separate websites frequently to find out if content on the site has been updated can take a long time. Aggregation technology helps to consolidate many websites into one page that can show the new or updated information from many sites. Aggregators reduce the time and effort needed to regularly check websites for updates, creating a unique information space or personal newspaper. Once subscribed to a feed, an aggregator is able to check for new content at user-determined intervals and retrieve the update. The content is sometimes described as being pulled to the subscriber, as opposed to pushed with email or IM. Unlike recipients of some push information, the aggregator user can easily unsubscribe from a feed.

Aggregation features are frequently built into web portal sites, in the web browsers themselves, in email applications or in application software designed specifically for reading feeds. The aggregator provides a consolidated view of the content in one browser display or desktop application. Aggregators with podcasting capabilities can automatically download media files, such as MP3 recordings. In some cases, these can be automatically loaded onto portable media players (like iPods) when they are connected to the end-user's computer.

By 2011, so-called RSS-narrators appeared, which aggregated text-only news feeds, and converted them into audio recordings for offline listening. The syndicated content an aggregator will retrieve and interpret is usually supplied in the form of RSS or other XML-formatted data, such as RDF/XML or Atom.

The variety of software applications and components that are available to collect, format, translate, and republish XML feeds is a testament to the flexibility of the format and has shown the usefulness of presentation-independent data.

News aggregation websites began with content selected and entered by humans, while automated selection algorithms were eventually developed to fill the content from a range of either automatically selected or manually added sources. Google News launched in 2002 using automated story selection, but humans could add sources to its search engine, while the older Yahoo News, as of 2005, used a combination of automated news crawlers and human editors.[3][4][5]

More advanced methods of aggregating feeds are provided via Ajax coding techniques and XML components called web widgets. Ranging from full-fledged applications to small fragments of source code that can be integrated into larger programs, they allow users to aggregate OPML files, email services, documents, or feeds into one interface. Many customizable homepage and portal implementations provide such functionality.

In addition to aggregator services mainly for individual use, there are web applications that can be used to aggregate several blogs into one. One such variety—called planet sites—are used by online communities to aggregate community blogs in a centralized location. They are named after the Planet aggregator, a server application designed for this purpose.

Feed aggregation applications are installed on a PC, smartphone or tablet computer and designed to collect news and interest feed subscriptions and group them together using a user-friendly interface. The graphical user interface of such applications often closely resembles that of popular e-mail clients, using a three-panel composition in which subscriptions are grouped in a frame on the left, and individual entries are browsed, selected, and read in frames on the right. Some notable examples include NetNewsWire, Flipboard, Prismatic, and Zite.[8][9]

Media aggregators are sometimes referred to as podcatchers due to the popularity of the term podcast used to refer to a web feed containing audio or video. Media aggregators are client software or web-based applications which maintain subscriptions to feeds that contain audio or video media enclosures. They can be used to automatically download media, playback the media within the application interface, or synchronize media content with a portable media player.

One of the problems with news aggregators is that the volume of articles can sometimes be overwhelming, especially when the user has many web feed subscriptions. As a solution, many feed readers allow users to tag each feed with one or more keywords which can be used to sort and filter the available articles into easily navigable categories. Another option is to import the user's Attention Profile to filter items based on their relevance to the user's interests.

^Luscombe, Belinda (2009-03-19). "Arianna Huffington: The Web's New Oracle". Time (Time Inc). Retrieved 2009-03-30. (subscription required (help)). The Huffington Post was to have three basic functions: blog, news aggregator with an attitude and place for premoderated comments.